Skip to main content

The BITSAVERS.ORG Documents Library: Royal Precision

The LGP-30, standing for Librascope General Purpose and then Librascope General Precision, was an early off-the-shelf computer. It was manufactured by the Librascope company of Glendale, California (a division of General Precision Inc.), and sold and serviced by the Royal Precision Electronic Computer Company, a joint venture with the Royal McBee division of the Royal Typewriter Company. The LGP-30 was first manufactured in 1956 with a retail price of $47,000.

The LGP-30 was commonly referred to as a desk computer. It was 26 inches deep, 33 inches high, and 44 inches long, exclusive of the typewriter shelf. The computer weighed approximately 740 pounds and was mounted on sturdy casters which facilitated movement of the computer.

The primary design consultant for the Librascope computer was Stan Frankel, a Manhattan Project veteran and one of the first programmers of ENIAC. He designed a usable computer with a minimal amount of hardware. The single address instruction set had only 16 commands. Not only was the main memory on magnetic drum, but so were the CPU registers, timing information and the master bit clock, each on a dedicated track. The number of vacuum tubes were kept to a minimum by using solid-state diode logic, a bit-serial architecture and multiple usage of each of the 15 flip-flops.

It was a binary, 31 bit word computer with a 4096 word drum memory. Standard inputs were the Flexowriter keyboard and paper tape (ten 6-bit characters/second). The only printing output was the Flexowriter printer (typewriter, working at 10 characters/second). An optional higher speed paper tape reader and punch was available as a separate peripheral.

The computer contained 113 electronic tubes and 1450 diodes. The 113 electronic tubes were mounted on 34 etched circuit pluggable cards which also contain associated components. Although 34 pluggable cards were used, there were only 12 different types of such cards. Card-extenders were available to permit dynamic testing of all machine functions. Six hundred and eighty of the 1450 diodes were mounted on one pluggable logic board.

The LGP-30 required 1500 watts when operating under full load. The power inlet cord was plugged into any standard 115 volt 60 cycle single phase line. The computer contained internal voltage regulation against power line variations of voltages from 95 to 130 volts. In addition to regulation of power line variations, the computer also contained the circuitry required to permit a warm-up stage. This warm-up stage minimized thermal shock to tubes to ensure long component life. The computer contained its own blower unit and directed filtered air, through ducts, to tubes and diodes, in order to ensure component life and proper operation. No expensive air conditioning needed to be installed if operated within a reasonable temperature range.

There were 32 bit locations per drum word, but only 31 were used, permitting a "restoration of magnetic flux in the head" at the 32nd bit time. Since there was only one address per instruction, a method was needed to optimise allocation of operands. Otherwise, each instruction would wait a complete drum (or disk) revolution each time a data reference was made. The LGP-30 provided for operand-location optimization by interleaving the logical addresses on the drum so that two adjacent addresses (e.g., 00 and 01) were separated by nine physical locations. These spaces allowed for operands to be located next to the instructions which use them. There were 64 tracks, each with 64 words (sectors). The time between two adjacent physical words was approximately 0.260 millisecond, and the time between two adjacent addresses was 9 x 0.260 or 2.340 milliseconds. The worst-case access time was 16.66 ms.

Half of the instruction (15 bits) was unused. The unused half could be used for extra instructions, indexing, indirect addressing, or a second (+1) address to locate the next instruction, each of which could increase program performance.

A truly unique feature of the LGP-30 was the way it handled multiply. Despite the LGP-30 being inexpensive, it had built in multiply. Since this was a drum computer and bits needed to be acted on serially as they were read from the drum, as it did each of the additions involved in the multiply, it effectively shifted the operand right, acting as if the binary point was on the left side of the word, as opposed to the right side as most other computers assume.

To further reduce costs, the traditional front panel lights showing internal registers were absent. Instead, Librascope mounted a small oscilloscope on the front panel. It displayed the output from the three register read heads, one above the other, allowing the operator to "see" and actually read the bits. Horizontal and vertical size controls let the operator adjust the display to match a plastic overlay engraved with the bit numbers. To read bits the operator counted the up- and down- transitions of the oscilloscope trace.

Original from Wikipedia

164
RESULTS
rss


PART OF
The BITSAVERS.ORG Documents Library
Additional Collections
Media Type
164
texts
Year
1
1964
4
1963
1
1961
5
1960
4
1959
2
1957
More right-solid
Topics & Subjects
98
program
53
program input
52
input
51
address
42
location
38
location instruction
More right-solid
Collection
Language
164
English
SHOW DETAILS
up-solid down-solid
eye
Title
Date Published
Creator
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: RPC-4000 Programming Manual
Topics: instruction, accumulator, word, location, upper, hex, lower, input, contents, lower accumulator,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: RPC-4000 Maintenance and Training Manual
Topics: phase, input, signal, nsc, typewriter, control, junc, punch, output, word period, control panel,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: K4-151 Nov1959
Topics: program, carriage, return, initializing, subroutine, pool, lines, sample, output, contents,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: H1-124 Oct1959
Topics: program, location, address, contents, dictator, instruction, coding, input, data, laudeman, coding...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: RPC-4000 Features Manual
Topics: accumulator, command, operand, computer, typewriter, instruction, upper, track, control, switch,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F2-96 Nov1959
Topics: program, pool, polynomial, reviewer, jodat, erfp, calvin, counter, input, mcbee, data processing,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: programWriteups :: J4-284-4 PROXY
Topics: track, punch, loading, loader, code, tape, reel, hex, proxy, program, reel format, key code,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 Subroutine Manual Oct60
Topics: location, accumulator, program, input, contents, instruction, code, decimal, routine, locations,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 12 4
Topics: gruppe, und, die, von, das, zellen, den, ausdruck, oder, und das, der gruppe, den zellen, den...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 11 6-12 6
Topics: ooooooi, xzoool, uoooo, joo, iqolwqoo, xzooo, iqlqiqo, uloo, iiooooooo, jjj
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: RPC-4000 Preliminary Programming Manual Apr60
Topics: accumulator, instruction, contents, word, memory, upper, lower, data, branch, lower accumulator,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 Schematics 1959
Topics: librascope, schematic, qnd, tolerances, diodes, fractional, incorporated, drawn, revisions, flip,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 Operations Manual
Topics: tape, instruction, typewriter, accumulator, input, computer, punch, switch, tape typewriter, paper...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-230 2
Topics: matrix, program, xxxx, location, address, coding, codes, conditional, contents, input, coding...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 Programming Manual Apr57
Topics: instruction, accumulator, program, location, binary, memory, result, contents, multiply, input,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: K2-71 Aug1959
Topics: hex, program, punch, punched, decimal, pch, repositional, loh, address, contents, western electric,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: Combined Line Catalog 1961
Topics: model, tape, typewriter, input, characters, punch, data, magnetic, punched, tape typewriter, paper...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: programWriteups :: K9-01.0 Program Checkout 1
Topics: program, code, checkout, input, print, location, hexadecimal, address, ddddd, button, sense switch,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: J5-186
Topics: program, sum, repositional, modifier, check, vacant, hex, binize, store, add, check sum, program...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: L1-92 Sep1959
Topics: program, sorting, block, area, address, search, jul, input, stored, initialize, sorting area, speed...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 24 2
Topics: die, den, inhalt, des, und, das, von, zelle, adresse, den inhalt, inhalt des, der zelle, inhalt...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: H1-121 May1959
Topics: program, xxxx, contents, floating, pool, address, input, instruction, exit, accumulator, floating...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: J4-184
Topics: punch, hex, vacant, digits, program, cnt, prepare, command, punched, program input, input codes,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: RPC-4000 Preliminary Product Information May60
Topics: instruction, typewriter, computer, accumulator, punch, modulo, repeat, switch, lower accumulator,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: programWriteups :: W1-01.0 Blackjack Game
Topics: program, blackjack, depress, column, switch, prints, cards, alphabetic, player, execute, sense...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 30 1
Topics: die, und, anfang, matrix, vektor, aufeinanderfolgenden, beginnend, bei, des, der matrix, beginnend...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 10 4
Topics: die, und, wird, das, des, codewort, wbrter, von, die adresse, die kaschine, adresse des, des...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: L1-49 Aug1958
Topics: program, code, word, sorting, routine, set, pool, temp, list, location, code word, sorting routine,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F2-185
Topics: program, pool, counter, address, boles, regulog, instruction, input, carriage, contents, program...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 24 1
Topics: die, wird, das, und, des, mit, von, fur, den, mit erweitertem, erweitertem bereich,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 30 0
Topics: die, von, und, beginnend, werden, fiir, mit, elemente, die elemente
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 11 4
Topics: die, ein, codewort, und, das, gruppe, liest, wwwwoooo, xioooo, der plan
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 Subroutine Manual Aug57
Topics: accumulator, input, contents, subroutine, program, location, decimal, instruction, address,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: ACT1 Compiler 1959
Topics: statement, symbol, program, operations, symbols, dim, iter, programmer, print, trn, statement...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F6-107 Apr1959
Topics: program, pool, prooram, address, probit, instruction, conditional, users, contents, input, location...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: H2-01.2 ROAR III Programming Manual
Topics: roar, location, address, instruction, symbol, program, depress, error, subroutine, tape, data...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: 11 7
Topics: xxxx, sequence, integer, input, program, decimal, instruction, binary, location, data, calling...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F6-105 Mar1960
Topics: erfp, program, loc, store, initialize, statistics, loop, compute, computed, pool, store loc, sample...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 Floating Point Interpretive System Programming Notes Nov59
Topics: program, floating, instruction, instructions, location, input, programmer, flexowriter, data, tape,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: 11 4
Topics: input, address, coding, instruction, program, codes, conditional, location, contents, corporation,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: H2-120 Feb1960
Topics: program, input, symbolic, symbol, lgpsap, pool, assembly, address, location, coding, assembly...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: LGP-30 ACT III Compiler Preliminary Manual
Topics: statement, program, iii, integer, error, overflow, operations, subroutines, data, tape, transfer...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: H1-22 0 Apr1957
Topics: address, instruction, contents, abstract, complex, interpretive, xxxx, location, operation,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: J4-187 Apr1960
Topics: punch, hex, vacant, digits, program, cnt, command, repositional, crnt, prepare, coding sheet,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: K3-156 Dec1959
Topics: program, routine, generalized, search, memory, contents, temp, location, zoooo, mcbee, search...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-229 2
Topics: xxxx, matrix, location, program, consecutively, multiply, initial, columns, rows, floating, initial...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F2-130 May1961
Topics: program, matrix, pool, floating, rij, burggrabe, prepared, address, ctr, input, floating point,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F4-222 Jan1961
Topics: ctr, sos, program, factorial, input, codes, lamm, analysis, loop, heading, input codes, factorial...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: J3-108
Topics: log, program, lamm, mantissa, printout, mask, characteristic, march, pool, subroutine, data output
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 11 1
Topics: mit, die, eine, und, codewort, sie, das, zahlen, zahl, der plan, das codewort
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: H1-33 0
Topics: routine, looping, xxxx, interpretive, located, instruction, program, programming, values,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-339 3
Topics: matrix, dpfp, location, subtract, elements, program, cij, precision, initial, input, precision...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: C2-155
Topics: program, pool, becker, nth, address, prepared, input, retl, roots, conditional, users organization,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: H1-02.0 PINT Program Description 1964
Topics: program, instruction, pint, location, code, accumulator, instructions, subroutine, address, xxx,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-329 3
Topics: xxxx, matrix, program, location, initial, locations, stored, boooo, floating, storage, initial...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: C2-35 0
Topics: coooo, quartic, program, roots, coefficients, store, equations, xuoooo, zotoo, xioool, quartic...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-439 4
Topics: matrix, transpose, storage, transposed, location, floating, dpfp, program, required, coding,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 24 3
Topics: wird, inhalt, des, xxxx, das, die, nach, eine, inhalt der, der inhalt, speicherzelle xxxx, der...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-430 4
Topics: xxxx, program, matrix, address, transpose, codes, contents, input, instruction, coding, program...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: K3-26 2
Topics: adresse, und, die, nach, spur, werden, nicht, einer, programm, das programm
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: J2-106 en
Topics: program, input, pool, decimal, mask, koenig, address, routine, exit, word, program input, program...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 13 2
Topics: und, des, die, schalter, poooo, druecken, schritt, flexowriters, nach, des flexowriters, nach...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: H1-24 3 1963
Topics: contents, accumulator, floating, interpretive, location, xxxx, logarithm, memory, instruction,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 30 4
Topics: die, von, fiir, ordnung, katrix, boooo, kann, mit, zelle
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: F4-208 May1960
Topics: program, sos, address, squares, input, coding, prepared, contents, data, instruction, coding sheet,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: C2-37
Topics: program, subroutine, iteration, input, transfer, pool, depress, coding, printed, button, transfer...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: L1-45 0
Topics: list, routine, mask, sorting, bits, corporation, mcbee, word list, sorting routine
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-140 0
Topics: program, matrix, address, prepared, codes, input, contents, instruction, carriage, retu, program...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 11 0R
Topics: die, und, das, zahl, uoooo, einer, doooo, bei
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: RPC-4000 :: H3-02.0 ACT IV Programming Manual
Topics: program, statement, input, processor, operations, typewriter, depress, procedure, output,...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 21 0
Topics: die, werden, wird, und, adresse, vor, des, anfangsadresse, modifier
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: D1-429 4
Topics: xxxx, matrix, transpose, program, storage, transposed, stored, sequence, locations, tions
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: en :: C1-37 6
Topics: program, yio, curve, accuracy, fit, input, polynomial, loc, address, conditional, curve fit, return...
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 12 0A
Topics: die, nach, druck, zahl, eine, ein, und, dezimalzakl
From the bitsavers.org collection, a scanned-in computer-related document. royalPrecision :: LGP-30 :: de :: 23 1
Topics: die, des, von, den, und, ausdruck, werden, inhalt, bei, inhalt des, des akkumulators, der plan, den...